title: Adrenomedullin delivery in microsphere-scaffold composite for remodeling of the alveolar bone following tooth extraction: an experimental study in the rat.
abstract: BACKGROUND
  Alveolar ridge resorption, as a significant problem in implant and restorative dentistry, has long been considered as an inevitable outcome following tooth extraction. Recently, adrenomedullin (ADM) is reported to be able to stimulate the proliferation and migration of various cells including osteoblasts. The purpose of this study was to investigate the influence of local ADM application in the tooth extraction socket in vivo.
  
  
  METHODS
  Chitosan micropheres were developed by an emulsion-ionic cross-linking method for ADM delivery. Poly (L -lactic-co-glycolic) acid (PLGA) and nano-hydroxyapatite (nHA) were used to prepare scaffolds to contain the micrspheres with ADM. In vivo experiment was evaluated by transplanting the composite into the rat socket right after the incisor extraction. After 4, 8, 12 weeks implantation, radiographic and histological tests were carried out to evaluate the effect of released ADM on the alveolar bone.
  
  
  RESULTS
  The microspheres had a spherical structure and a relative rough and uniform surface, and the particle size was under a normal distribution, with the average diameter of 38.59 μm. The scaffolds had open and interconnected pores. In addition, the high porosity of the composite was 88.93%. Radiographic and histological examination revealed that the PLGA/nHA/CMs/ADM composite could accelerate the alveolar bone remodeling and reduce the residual ridge resorption compared with the PLGA/nHA/CMs scaffold.
  
  
  CONCLUSIONS
  The results of this study suggest that local application of ADM has the potential to preserve the residual alveolar ridge and accelerate the alveolar bone remodeling.
authors.affiliation: Implant center, Stomatological hospital, Jilin University, 1500# Qinghua Road, Chaoyang District, Changchun, China. zhouym@jlu.edu.cn.
authors.forename: Lin
authors.initials: L
authors.lastname: Wang
authors.forename: Ling
authors.initials: L
authors.lastname: Zheng
authors.forename: Chunyan
authors.initials: C
authors.lastname: Li
authors.forename: Shujun
authors.initials: S
authors.lastname: Dong
authors.forename: Lan
authors.initials: L
authors.lastname: A
authors.forename: Yanmin
authors.initials: Y
authors.lastname: Zhou
mesh_terms: D053607:Adrenomedullin / Q000378:metabolism* / Q000494:pharmacology*; D000818:Animals; D001672:Biocompatible Materials / Q000378:metabolism / Q000494:pharmacology; D015519:Bone Density / Q000187:drug effects; D016723:Bone Remodeling / Q000187:drug effects*; D048271:Chitosan / Q000737:chemistry; D004337:Drug Carriers / Q000737:chemistry*; D017886:Durapatite / Q000737:chemistry; D006801:Humans; D007700:Kinetics; D019344:Lactic Acid / Q000737:chemistry; D008297:Male; D008863:Microspheres; D049329:Nanostructures / Q000737:chemistry; D011100:Polyglycolic Acid / Q000737:chemistry; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D051381:Rats; D017208:Rats, Wistar; D013696:Temperature; D054457:Tissue Scaffolds; D014081:Tooth Extraction
chemical_list: D001672:Biocompatible Materials; D004337:Drug Carriers; D053607:Adrenomedullin; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid; D048271:Chitosan; D017886:Durapatite